1. Field of the Invention
This invention relates to a roof support for a mobile mine drilling machine and more particularly to a roof support for protecting the drill operator and operatively mounted to facilitate tramming of the machine and positioning to support the mine roof during roof drilling and bolting operations.
2. Description of the Prior Art
In underground mining, it is the present practice to support the roof of the excavated or mined areas with roof bolts that are inserted in holes drilled in the mine roof. The roof bolts serve to tie the overhead strata of different materials to each other and reduce horizontal shifting or sliding of the different strata relative to each other. This manner of roof support minimizes the possibility of sections of the roof falling and injuring personnel in the mine. The roof bolts hold rectangular bearing plates in place adjacent the surface of the roof to provide additional bearing support for the roof.
In order to provide the desired roof support by bolting, it is necessary to form bore holes to a given depth in the roof with a roof drill. The depth of the bore hole may vary from several feet to ten feet or more, depending on the type of strata located above the roof. It is essential that the bore hole terminate in a stratum that provides a good anchor for the expansion member on the roof bolt. It is the conventional practice to drill a plurality of holes in a given arrangement across the entry at spaced intervals in the mine roof to provide a standard bolt pattern. To this end the roof drill is maneuvered in the mine entry for drilling bore holes at preselected locations in the mine roof by a self-propelled vehicle.
In one embodiment the roof drill, such as a rotary or a rotary percussion type, is pivotally connected to a forwardly extending boom that is connected to the body of the self-propelled vehicle. A suitable linkage mechanism raises and lowers the boom to vertically raise the drill to the required elevation to drill a bore hole to a preselected depth in the mine roof. It is also known to drill bore holes in accordance with a preselected bolt pattern by a mast-type drill that is mounted for slidable vertical movement on a mast supported on the body of the self-propelled vehicle. Suitable hydraulic devices are operable to vertically raise the mast together with the drill into drilling position adjacent the mine roof. The lower portion of the mast is stabilized on the mine floor to brace the drill as it is vertically raised to drill a bore hole in the mine roof.
The conventional roof drilling operation involves drilling of an unsupported section of the mine roof, and, after periods of continual drilling, a section of the unsupported roof could be sufficiently weakened to the extent that the roof could collapse resulting in serious injury to the operating personnel and damage to the drilling machine. Therefore, it is known to provide protective canopies for drilling machines as disclosed in U.S. Pat. No. 3,865,197 illustrating a protective canopy for a mobile-type drilling machine.
There is need for a roof support associated with a mobile mast-type drilling machine that provides overhead roof support for the drill operator when the mast-type drill is moved into roof drilling position and a roof support arrangement that may be transported by the self-propelled vehicle when the drill is moved to preselected locations in the mine entry.